A phase-frequency characteristic of the phase detector and method for detecting frequency characteristics

The present invention relates to a phase frequency detector detects the phase and frequency characteristics. Wherein the phase frequency characteristic detector, comprising adjustable dual phase signal generator, a phase modulation method detecting means, wherein one input port connected to one output port of the phase detector the phase modulation method dual variable signal generator, the other way an output port through another input port of the phase detector and the modulation method is connected to a network under test, further comprising analog to digital conversion circuit and the phase of the output voltage of the phase detecting unit connected to the modulation method, the output of the analog to digital conversion circuit via the digital control unit Dual signal generator with adjustable phase input terminal connected to the digital control unit respectively connected to the display unit, the setting unit. The present invention is simple operation, can avoid a large area of ​​the phase error detection means detects a phase modulation method, a large measurement accuracy, can be measured directly determines network is a lead lag network or a network, and obtaining the measured phase shift network.